The main objective of this research plan is to study several aspects of fluid and electrolyte transport in ocular membranes. The movement of water and ions across the cornea, lens, and ciliary epithelium depends on two factors: a) the permeability of the membrane determined by the physical and histological structure and b) the driving forces mainly produced by local and distant energy yielding chemical reactions. Although each of these two individual factors have been separately studied in cornea, lens, and ciliary body, the way in which they are coupled to produce the translocation of ions remains poorly understood. Using the formalism of the irreversible thermodynamics, emphasis will be put on the link of metabolism to ionic and water transport. The study of active ionic transport in cornea, lens, and ciliary body is fragmentary. Of these trasnmissions, mainly the cornea and in less degree, the ciliary epithelium have been studied with the Ussing-type methodology. Furthermore, transport characteristics seem to differ among different species. The long-term goal is to fully characterize driving forces, mechanisms, and types of ionic translocation in cornea, ciliary body, and lens of a given experimental animal.